DE1176161B - Multi-stage electrothermal device (cascade) - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

Boarding school Class: F 25 b

GERMAN

PATENT OFFICE

EDITORIAL

German class:

Number: File number: Registration date: Delivery day:.

17a-20

1176 161
S 83371 Ia / 17 a
January 21, 1963
20th August 1964

The invention relates to a multi-stage electrothermal Device (cascade) for cooling or heating, in which the connection points with the the respective steps forming ends of the power supply line and the current discharge line on a colder one Temperature level as the second stage working on the first stage and any existing one further stages are at a higher (warmer) temperature level than their other ends.

With devices of this type, which are used in particular for cooling, care must be taken Make sure that connections between areas with different temperature levels are largely thermally conductive be avoided in order to increase the efficiency of such arrangements through thermal bridges which flow back the heat in the opposite direction to the heat transport direction of the electrothermal device can not adversely affect.

In order to take this fact into account, some known cascades are used for each one Level the tension to (Fig. 1). With such an arrangement one must accept that - apart from the level at the warmest level - the electrical connections of the at other levels a thermal bridge between the joints at lower temperatures and the ambient temperature. It is assumed that the temperature of the mains terminals corresponds to the temperature of the warmest setting.

In any case, these known devices have an undesirable location at one point Thermal bridge. You can therefore rely on the separate electrical supply for each individual Forego stage and form the device according to FIG. These are marked with 18 and 19 Connecting lines unwanted thermal bridges, such as the connecting lines 8 and 9 of the Fig. 1 correspond.

In order to avoid such undesirable connections, one can refer to Dahlberg (magazine for Applied Physics, Issue 10/1958, p. 366) train the cascade so that the electrical connection between the individual stages between a cold end contact point of the warmer sub-stage and a warm end contact point of the colder sub-stage is arranged (FIG. 3). But this has the advantage been dispensed with to be able to use connections lying on the same side of the block.

The invention is also based on the object of preventing the undesired heat transport in the heat transport direction of the cascade of opposite multistage electrothermal devices
(Cascade)

Applicant:

Siemens-Electrogeräte Aktiengesellschaft,

Berlin and Munich,

Munich 1, Oskar-von-Miller-Ring 18

Named as inventor:

Dr. Heinz Müller, Erlangen;

Direction through thermal bridges of the aforementioned Kind to be avoided to a large extent. For this purpose, according to the invention, the power supply and the Current dissipation of the second stage and any further stages that may be present in whole or in part formed by conductors made of electrothermal material. In this way, through suitable doping and appropriate polarity, one can achieve that the conduction used for the electrical connection of the stages in the working direction of the cascade transported so that the opposite to the in this line by the action of the thermal bridge Harmful amount of heat flowing in the direction of transport of the cascade is compensated.

The invention can be used with particular advantage for such cascades in which all stages are composed of thermoelectric blocks of the same structure. Only through the use of materials exhibiting the Peltier effect for the electrical connecting lines is such an arrangement possible without significant thermal bridges. In this case, the blocks of different stages will be electrically connected to one another via electrothermal element legs of suitable doping (p- or η-conductive). You can then lead the power supply and the current discharge of each stage to the outside in such a way that they lead directly to the outside from the warm side of the first stage, which operates at the highest (warmest) temperature level, while the current leads and current leads of the other stages only after switching in between be led to the outside by electrothermal material.
In the drawing, examples of known designs (Fig. 1 to 3) and an embodiment of the invention are shown schematically. Show in it

409 657/99

F i g. 1 to 3 schematic representations of known cascades,

F i g. 4 and 5 show a schematic and top view of exemplary embodiments of the invention.

In Fig. 1 a two-stage cascade is shown, at which the more powerful level 1 is at the higher (warmer) temperature level. The electrical supply is provided for the first and for the second stage via separate lines 6, 7 and 8, 9. The feed lines 8, 9 of stage 2 (lower [colder] temperature level) are like the feed lines 6, 7 of the first stage connected to the mains terminals (not shown). Since the temperature of the Mains terminals correspond to the temperature of the environment, the leads 8, 9 form undesirable Thermal bridges.

The F i g. 2 shows a view of a two-stage cascade, in which the first (warmer) stage out of four Blocks and the second (colder) stage consists of one block. All blocks are the same as one another. This has the advantage that only one type of block needs to be produced. Located at all blocks the electrical connections are on the respective »warm« side. However, it is also disadvantageous here that the metallic connections 18, 19 between sites different temperatures represent undesirable thermal bridges.

FIG. 3 shows another known cascade in which the electrical leads 21 and 22 and 21a, 22a are arranged on different sides of each block of stage 1. The connection of the cascade to the energy source takes place via lines 21 and 22 a. Both lines are assigned to the warm side. In this cascade, the current flows from the energy source via line 21, through the left block of stage 1 in the figure, via one of the connecting lines 22 , 23 to stage 2, then through the other branch 23 and through 21 a to the one in the F i g. 3 right block of stage 1 and from there via the feed line 22 α back to the energy source. This avoids a connection between areas of different temperatures which is detrimental to the efficiency of the arrangement. However, blocks of different properties are required, namely, firstly, blocks in which the electrical connections are on one side (level 2) and, on the other hand, blocks in which the electrical leads are arranged on opposite sides of the block (level 1). This increases the cost of manufacturing such cascades. In addition, it is necessary to determine the requirements of the individual block types very precisely in advance.

Finally, such a device has the disadvantage that once selected and manufactured Circuit of the cascade is difficult to change.

These disadvantages become apparent in the case of the systems shown in FIGS and 5 illustrated embodiments of the invention avoided. The external structure corresponds to that in F i g. 2 cascade.

The blocks of the FIG. 4 shown cascade are provided with elements that have a square Have cross-section, while the elements of the cascade shown in Fig. 5 have a circular cross-section to have.

The electrical connections of level 1 are labeled 6 and 7 and those of level 2 are labeled 8 and 9.

The thermocouples of both stages are limited by heat exchange plates 31, 32 and 33.

Plate 31 is on the cold, plate 33 on the warm side of the cascade; the Plate 32 forms the link between the two stages and is therefore at an intermediate temperature. At two current bridges 34 and 35 are arranged on the warm plate 33 in an electrically insulated manner. With the plate

34 is a p-type leg 36, with the plate

35 an η-conductive leg 37 in metallic contact. On the opposite of these contacts On the side, the element legs 36 and 37 are in contact with the leads 8 and 9 of the second stage. The current bridges 34 and 35 are also provided with electrical connections 38 and 39.

For the two-stage operation of this device, the lines 6 and 39 are connected to the poles of the Connected energy sources. The two electrical cable runs 8, 36, 34 and 38 or 9, 37, 35 and 39 connect the plates 32 and 33 in a thermally conductive manner and thus constitute an undesirable thermal bridge between the intermediate temperature range and the warm side of the cascade. In the two Due to the existing temperature gradient, cable runs would generate heat from 34 to 8 or flow from 35 to 9. A part of both lines consists of electrothermal material, the is traversed by the working current of the cascade. With the selected polarity, there is one in both legs Amount of heat in the direction of the heat exchange plate located at an intermediate temperature 32 transported to the warm side 33 of the cascade. In both electrothermal parts of the Due to the Peltier effect, supply lines are generated in the opposite direction transported to the amount of heat flowing due to the temperature gradient. These amounts of heat thus at least partially compensate each other. With a suitable dimensioning of the arrangement one can achieve that the harmless amount of heat transported in the first direction is greater than is the amount of heat flowing due to the temperature level, which reduces the efficiency.

The new arrangement of a cascade also has the considerable advantage that the circuit and thus the operating mode can be changed very easily. For example, if you leave the contacts 38 and 39 open and connects the leads 6 and 7 to the poles of an energy source, so you can Only operate the cascade in one stage with the first, more powerful stage. Furthermore is an independent Operation of both stages is possible if the supply lines 6 and 7 or 38 and 39 are connected separately to the Pole of an energy source connects. In this case you can, for. B. the current in the first stage keep constant and vary that of the second stage in order to adjust the temperature or the electrical To regulate the performance of the cascade.

Claims (3)

Patent claims: 1. Multi-stage electrothermal device (cascade) for cooling or heating, in which the ends of the power supply line and forming the connection points with the respective stages the current dissipation of those working at a colder temperature level than the first stage second stage and any existing other levels are at a higher (warmer) temperature level than the others Ends, characterized in that the power supply line and the current discharge line of the second stage and, if applicable, further stages in whole or in part Conductors are formed from electrothermal material. 2. Electrothermal cascade according to claim 1, wherein all stages of the cascade from are composed of electrothermal blocks of the same structure, characterized in that that the blocks of different stages via electrothermal element legs of suitable doping (p- or η-conductive) are electrically connected to each other. S. 3. Electrothermal cascade according to claim 1 or 2, characterized in that the power supply line and the current dissipation of those working at the highest (warmest) temperature level first stage from the warm side directly to the outside, while the power supply lines and the current dissipation of the other stages only after the interposition of electrothermal Material can be led to the outside. Considered publications:
German Auslegeschrift No. 1132 940;
U.S. Patent No. 2,734,344;
Journal of Applied Physics, 1958, Issue 10, 366. 1 sheet of drawings 409 657/99 8.64 @ Bundesdruckerei Berlin